At present, various power generating systems are utilized. However, from an ecological point of view, the use of natural energy attracts attention. For example, a tower type solar heat turbine system generates heat energy by reflecting sunlight by a heliostat composed of a plurality of reflecting mirrors installed on the ground, thereby focusing sunlight on a solar heat receiver of an upper portion of a tower installed on the ground.
In such a tower type solar heat turbine system, a high-pressure working fluid is generated by compressing a working fluid such as air in a compressor which is rotationally driven. The high-pressure working fluid is heated in the solar heat receiver, whereby a high-temperature working fluid is generated.
The high-temperature working fluid rotationally drives a turbine. The compressor and a turbine generator are rotationally driven by the turbine, and therefore, electric power is generated with this (refer to, for example, Patent Documents 1 to 3).
Further, in the solar heat turbine systems as described above, there is also a solar heat turbine system in which a part of a high-pressure working fluid which is in a process of being compressed in a compressor is bled as a bled working fluid. Further, as the solar heat turbine system, in addition to the tower type described above, there are a trough type, a beam-down type, and the like.
However, in the solar heat turbine system as described above, for example, there is a case where a so-called trip in which an electrical load connected to the turbine generator disappears due to abnormality or the like of the turbine system or an electrical system occurs. In this case, a mechanical load acting on the turbine generator is also rapidly reduced, and therefore, there is a case where so-called over-speed or surging is generated in the turbine generator.
Therefore, Patent Document 3 discloses causing a high-pressure working fluid to bypass a solar heat receiver from a compressor to a turbine, discharging the high-pressure working fluid from the compressor to the outside, and restricting the high-pressure working fluid which flows from the compressor to the solar heat receiver, if a trip occurs.